1. Field of the Invention
This invention relates to a machine for pulverizing concrete sheets or slabs, and more particularly to a machine for pulverizing concrete roadbeds having reinforcing steel therein, where the machine is moved along the roadbed during the pulverizing operation. The machine recycles the roadbed by reducing it to concrete aggregate and scrap steel. It accomplishes in one operation that now requires six steps in removal of deteriorated concrete roads.
2. Description of Related Art
The replacement of concrete roadways creates a unique and troublesome disposal problem whenever large and bulky concrete slab or sheet structures must be removed from the work site. Such large structures are unsuitable for disposal in landfills unless broken up into small pieces because they tend to create voids underground which prevent adequate filling and compaction. While air and hydraulic hammer machines have been developed to break up such concrete structures into smaller pieces, these machines are particularly unsuitable when the concrete has reinforcing steel embedded therein. Even after hammering, concrete tends to adhere to the steel, resulting in tangled steel and concrete debris, which is difficult to move and dispose of. The reinforcing steel itself is usually not reclaimable because of the exceedingly high concrete content that adheres to it. This material is typically trucked to remote disposal sites for inadequate disposition, for no better disposal or recycling program is known for such material. The hauling of this material to remote sites adds to the cost of reconstruction, and the loss of the steel and concrete material for recycling creates a needless economic loss to the owner of the material.
In the reconstruction of roadbeds the old concrete roadbed is typically hammered by means of machines to reduce the size of the concrete and steel fragments to manageable proportions, and these fragments are hauled away. The new roadbed is then filled and graded, and new concrete and reinforcing steel are applied to create a new road. A significant proportion of the total cost of building such a road is attributable to the cost of removing the old roadway, and no significant return is achieved through any recycling process.
Current road removal of deteriorated concrete roads involves a multiple step process for removing the old concrete road. First the concrete road is cracked such as by a plurality of jackhammers, then a “rhino horn” device lifts up the cracked roadbed. Then the steel rods or mesh is sawed or burned through to create sections of roadbed. The sections can be hauled to a landfill or a crusher caravan can first crush the concrete roadbed sections to a primary size aggregate and then a secondary crusher reduces the size of the aggregate to a desired size and the steel rods or mesh can be separated. Each of the above steps requires a different piece of equipment in a caravan traveling down the road and is labor intensive. What is needed is a machine to process old steel reinforced concrete roadbeds into concrete aggregate and recyclable scrap steel by continuously pulling up the roadbed, reducing the concrete recyclable concrete aggregate and separating out the steel mesh or rods as the machine travels along the road.
In the applicant's prior U.S. Pat. No. 4,309,126 a machine for separating concrete from steel for tearing up a roadbed and recycling it was presented. The machine used a wedge to pick the concrete pavement off the roadbed and lift it to an anvil for presentation to hammers, which removed the concrete from the steel reinforcing rods however the steel reinforcing rods would have to be disassembled for recycling which was labor intensive. Further the reinforcing rods were forced up over the driver on top of the machine, which required a ramp and a considerable amount of energy to force the steel rods up and over the top of the machine. There were many drawbacks to having the steel passing over the top of the machine such as inhibiting turns, weight, limitations of machine configuration due to height and possible safety issues. Further, the tracks on the machine were aft of the wedge, which is not ideal. It is better to pull the wedge under the pavement than to push it. Further the tracks were in a fixed position which made it harder to transport the machine since it is necessarily wider than a lane of a roadway and was longer than wide. The hammers in the applicant's prior machine had a small footprint and the hammers had to traverse the surface of the road for the foot of each hammer to impact on the entire surface of the pavement.